firefox: try to fix musl build

srcpkgs/firefox/patches/fix-tools.patch

@@ -26,3 +26,19 @@
    return base;
  }
  
+--- tools/profiler/core/platform-linux-android.cpp.orig
++++ tools/profiler/core/platform-linux-android.cpp
+@@ -715,11 +715,13 @@
+ void TickSample::PopulateContext(void* aContext)
+ {
+   MOZ_ASSERT(aContext);
++#if defined(__GLIBC__)
+   ucontext_t* pContext = reinterpret_cast<ucontext_t*>(aContext);
+   if (!getcontext(pContext)) {
+     context = pContext;
+     SetSampleContext(this,
+                      reinterpret_cast<ucontext_t*>(aContext)->uc_mcontext);
+   }
++#endif
+ }
+